Bleaching apparatus



July 6 1926. 1,591,070

R. B. WOLF BLEAcHING APPARATUS Filed Feb- 27. 1925 2 sheets-sheet 1 7 YIIIIIIIII INVENTOR L ATTORNEYS Patented July 6, 1926.

- UNITED STATES ROBERT B. worn, or NEW Yonx, 1;. Y.

BLEACHING APPARATUS.

Application filed February 27, 1925. Serial No. 11,974.

This invention relates to rotary pulp bleachers, and particularly to improvements therein which permit operation with pulp of materially greater density than that used heretofore.

Rotary bleachers of various kinds, including spherical, cylindrical and inclined cylindrical types, are known. Such bleachers can be used satisfactorily with low density pulp containing not to exceed 8 to 10% of fibre. Any material increase in the density of the pulp so that the latter approaches a non-fluid state increases the tendency of the pulp to ball or form into lumps which are not disintegrated during the operation of the machine. Under this condition the bleach cannot penetrate the pulp and mix thoroughly with the fibre. When the pulp is discharged after operation for the usual time, the lumps have brown centers of unbleached material and the pulp is not suitable for the production of high grade paper. If the bleaching time is increased the fibres near the surfaces of the lumps are injured. Consequently it is not practicable to use rotary bleachers of'the usual types for thick pulp bleaching.

It is the object of the present invention to provide rotary bleachers which facilitate the uniform action of the bleach on all of the fibre and the consettuent production of bleached pulp of a big er quality.

Further objects and advantages of the invention will be apparent as it is better understood by reference to the following specification and accompanying drawing, in which- Fig. 1 is an axial section through a bleach er of the spherical type embodying the invention;

Fig; 2 is a| transversesection through the structure illustrated in Fig. 1;

Fig. 3 is a longitudinal section through a cylindrical type bleacher;

' Fig. 4 is a transverse section through the structure illustrated in Fig. 3; and

Fig. 5 is a longitudinal section through an inclined cylindrlcal bleacher.

v To obviate the difliculty experienced heretofore in the formation of lumps in the pulp, I have provided bleachers in which the pulp is constantly agitated during the bleaching operation whereby the lumps are-broken up and the fibres are mingled thoroughly with the bleach. I have provided also for the introduction of air to facilitate the oxidizing. action which otherwise occurs ver slowly in closed bleachers. Provision is ai so made for the withdrawal of air from the bleacher so that the air introduced can pass through thus distributed throughout the pulp mass to ensure the most effective-oxidation during the bleaching operation. The bleacher shell is rotated by the application of power through any usual or suitable 1 devices for this purpose, and air is supplied by a compressor which can be connected to one end of the stationary shaft, the other end being connected to a suitable exhaust pipe so that any disagreeable fumes resulting from the bleaching operation are not discharged directly to the surrounding atmosphere.

Referring to Figs. 1 and 2 of the drawing, 5 indicates a shell spherical in form and constructed of metal in the usual manner. It is provided with trunnions '6 whereby it is sup orted in suitable bearings for rotation. ower is applied to the shell to rotate it through a suitable frame and earing (not shown) or other mechanism a apted for this purpose. A man-hole with a suitable cover 7 is provided to permit the introduction and withdrawal of the pulp, the apparatus being intended for batch operations.

A plurality of arms 8 are secured to the inner surface of the shell 5 and project into the space which is filled with pulp for the These arms may be tapered in form although this is-not essenbleaching operation.

tial. They are arran d as indicated in Figs. 1 and 2 about t e periphery of the spherical shell and are perpendicular to the axis thereof. A hollow shaft 9 extends through the trunnions 6, being supported 1n any suitable manner to reinain statlonary while the s e r t t s. Arms 1 a e ed to the shaft and extend downwardly therefrom in a perpendicular direction. Preferably they are provided with passages 11 which communicate with the interior of the hollow shaft 9 so that air introduced at the end 12 of the shaft 9 can pass downwardly through the passages to be disseminated thus through the mass of pulp. The end 13 of the shaft 9 is closed except for a pipe 14 which extends therethrough and projects upwardly, forming an arm 15 having a passage 16 therethrough. The air which is forced into the bleacher during the bleach' ing operation escapes through the passage 16 and the pipe 14 and is discharged thus from the bleacher.

- In Figs. 3 and 4, I have shown the application of the invention to a rotary cylinder 17 which, being intended likewise for batch operations, is provided with a man-hole having a cover 18. The cylinder is mounted on trunnions 19 which may be supported in suitable bearings andis provided on=its interior surface with a plurality of inwardly directed radial arms 20 which may be tapered or not as desired. These arms are staggered with reference to a plurality of downwardly directed arms 21 which are mounted on a hollow shaft 22 extending through the trunnions 19. The arms 21 are provided preferably with passages 22 communicating with the interior of the shaft which is adapted to receive air through the end 23. The air is thus distributed to the mass of pulp within the shell. The end 24 of the shaft is closed except for a pipe 25 having branches 26 which extend upwardly and are provided with passa es 27 through which air escapes from the leacher. The shell 17 is rotated by the application of power through a gear train or other device for this purpose.

In Fig. 5, a cylinder 28 is arranged to permit the application of the invention in continuous bleaching operations. The cylinder may besupported'for rotation and adapted to be driven through any suitable mechanism. A feeding device 29 directs the pulp into the cylinder at one end thereof and the bleached pulp. escapes through an outlet 30 at the opposite end thereof, the passage of the pulp through the bleacher being effected by gravity or displacement and the continued rotation of the cylinder. A plurality of inwardly projecting radial arms 31 which may be tapered or not as desired are secured to the inner wall of the cylinder 28 in staggered relation to a plurality of arms 32 whichproject downwardly from a shaft 33. The shaft is stationary and is supported in any suitable manner to permit rotation of the cylinder.

In the operation of the apparatus as will be; readily understood the pulp is supplied t h leacher 9 511?! in bfiwhes or contiguously. This pulp. may have a relatively high concentration so as to form a substantially non-fluid mass which in ordinary types of bleachers cannot be treated satisfactorily because of the difficulty of disseminating the bleach through the mass of fibres. In the apparatus as described the rotation of the shell causes the inwardly projecting arms thereon to pass repeatedly between the arms on the stationary shaft with the result that lumps of fibre formed in the bleacher are torn apart and the pulp and the fibre .are mingled constantly during. the operableaching with the minimum destruction of fibre during the bleaching operation. By utilizing the apparatus described it is possible to bleach concentrated pulp effectively and rapidly with consequent economy and improvement in the quality of the bleached product.

Various changes may be made in the details of construction of the apparatus including the reversal of the mechanism to permit rotation of the shaft on the arms thereof while the shell is held stationary, the beating and agitating effect being substantially the same in either case. Other changes can be made within the spirit and without departing from the invention or sacrificing any of the advantages thereof.

I claim:

1. In a pulp bleaching apparatus the combination of a shell, a shaft extending through the shell, arms on the shaft and shell arranged in staggered relation, and means for causing relative rotation of the shaft and shell whereby the arms respectively thereon are moved relatively to each other to disintegrate and agitate'the mass of .pulp and to prevent the formation of. lumps in the shell, said shaft and the arms attached thereto having passages for the introduction of air which is thereby disseminated through the mass of pulp.

2. In a ulp bleaching apparatus the combination ofa shell, a shaft extending through the shell, arms on the shaft and shell arranged in staggered relation, and means for causing relatlve rotation of the shaft and shell whereby the arms respectively thereon are moved'relatively to each other to disintegrate and agitate the mass of pulp and to prevent the formation of lumps in the shell, said shaft and the arms attached theretQ ha ng passages for the introduction of air which is thereby disseminated through the mass of pulp, and means for withdrawing air from the shell.

3. In a pulp bleaching apparatus, the combination of a shell, inwardly extending arms on the shell, a shaft extending through the shell, arms on the shaft arranged in staggered relation relative to the arms on the shell, means for causing relative rotation of the shaft and shell whereby the arms thereon are moved relative to each other to agitate the mass of pulp to prevent the formation of lumps, the shaft and the arms thereon being hollow for the introduction of air which is thereby disseminated through the massof pulp, and a discharge pipe within the shaft for withdrawing air from the shell.

4. In a pulp bleaching apparatus the combination of a rotatable shell, inwardly extending arms on the shell, a stationary shaft extending through the shell, arms on the shaft extending substantially throughout the length of the shell and arranged in staggered relation relativeto the arms on the shell, means for rotating the shell whereby the arms on the shell are moved relative to the arms on the shaft to agitate the mass of pulp charge pipe within the hollow shaft for with-.

drawing air from the shell.

5. In a pulp bleaching apparatus, the combination of a shell, inwardly extending arms on the shell, a shaft extending through the shell, arms in the shaft arranged in staggered relation relative to the arms on the shell, means for causing relative rotation of the shaft and shell whereby the arms thereon are moved relative to each other to agitate the mass of pulp to prevent the formation of lum s, the shaft and the arms thereon being hol 0w for the introduction of air which is thereby disseminated through the mass of pulp, and a discharge pipe within the shaft having an open end which pro-- jects through the wall of the shaft and communicates with the interior of the shell for withdrawing air from the shell.

'6. In a pulp bleaching apparatus, the com bination of a rotatable shell, inwardly extending arms on the shell, a stationary shaft extending through the shell, arms on the shaft arranged in staggered relation relative to the arms on the shell, means for rotating the shell whereby the arms on the shell are moved relative to the arms on the shaft to agitate the mass of pulp and prevent the formation of lumps, the shaft and the arms thereon being hollow for the introduction of air which is thereby disseminated through the mass of pulp and a discharge pipe lying within the hollow shaft and having an open end which projects upwardly through the wall of the shaft and communicates with the interior of the shell adjacent the upper side thereof for withdrawing air from the shell.

In testimony whereof I aflix my signature.

ROBERT B. WOLF. 

